X-ray system



Dec. 27, 1949 g. T. ZAVALES X-RAY SYSTEM Filed June 14, 1945 INVENTOR C.7: Z/YV/YZES. WWW

ATTORNEY Patented Dec. 27, 1949 UNITED PATENT OF 'FI'CTE.

X-BAY SYSTEM Application June 14-, 1945, Serial No. 599,334

7; Claims. (01. 2501;0,0)

The present invention relates to- X-ray appara-tus and more particularlyto an energizing system for an X-raytube wherein an indicator isemployed to signal the operator during operationof the system thatvarious parts thereof are properly functioning.

In high tension X-ray systems it is now quite customary to employ afull-wave bridge circuit rectifier arrangement so that the X-raytubeisenergized by high potential; unidirectional electrical energy;However, should one of the rectifying valve tubes fail for any reasonthere has been no way in which this fact is ascertainable resulting inperhaps many faulty radiographs before discovery; with attendant wastageof film in addition to the remaking of the exposure.

It is accordingly the primary object of the present invention toeliminat the. above n ed isadvantages by the provision of an indicator tsignal or indicate, to the operator whether or not the rectifying valvesare; properly iunctioning.

Another object. of the resent invention is, the provision of anindicator included in the low volt.- age metering circuit which willgive an accurate indication to an operator whether or not the high,voltage rectifying valve tubes are functioning properly.

Further objects of the present invention will become obvious tothoseskilled in the art by ref-. erence to the accompanying, drawing whereinthe single figure is a schematic illustration oi X- ray systemconstructed in accordance with the present invention.

Referring now to. the drawin in detail. the circuit arrangement ingeneral is very similar to that shown and described in Patent No.2,322,404, issued to Louis L. Weisglass on- June Z2, 19.43., andassigned to the same assign-ee as the present in! vention. Theapparatus, comprises a high tension transformer 5. having its primarywinding 6 con-.- nected to a source of A. C. current of the usual;commercial potential Ll, L2. The secondary winding i of this hi h tenion. rans-mime! is. connected by a conductor 8 to, the cathode andanodeof a pair of high voltage rectifying, valve tubes 9 and Ill,respectively, while the remaining.

end, of this secondary winding l is similarly con.-

nected y a conductor [2 to the cathode and anode of a further pair ofhigh voltage 1ectify-. ing valve tubes l3v and I4, respectively. Theserectifying valve tubes; are of the thermionic type and have theircathodes heated from the customary low voltage transformer which has notbeen shown tor simplicity.

An X-ray tube l5; has. its anode; cqnnccted by a conductor [6 to the,cathode oi the respec: tive valve tubes to and M while its; thermioniccathode is similarly connected by a conductor H: to the anode of therespective voltage hectifying valve tubes 9. and t3, thus completing a.full wave rectifying bridge circuit of the usual type. The thermioniccathode of the, X-ray tube, l5 receives heating energy from a. lowvoltage, transformer 18. the primary winding of which may; be connectedto. the same commercial; source of supply Ll, L2 as. the primary winding6; of the high voltage transformer 5.. Thesecondarv winding 1 isconnected to ground G.- at its. midpoint.

and a condenser I9; is connected series; Willi-1' the secondary winding1 to compensate, for the capacity effect in the latter windin In orderto. measure; the trueuseful current supplied to. the. X-raytube- IS. adirect current meter 22 of the DArsonval type. is, connected to a bridgerectifying circuit. similar to. the X-ray tube, so that unidirectionalcurrent is supplied to the; meter 22. For this purpose one side of themeter 22 is connected to the cathode of a pair of low voltage.rectifier-s 23: and 24., which may be thecopper oxide type known asRectox but prefie-rably are mercury filled rectifiers as mentioned inthe above noted Patent- No. 2,322,4(14, while the other side of themeter 22. is connected to the anodes of a. similar pair of rectifiers.25; and 26, and a condenser 21f is shunted across. the meter 22 as aprotective. capacitor for the meter.

lihe anode and cathode of the respective rectifiers 23 and 25: aregrounded as at. G while the anode and cathode of the respectiverectifiers 2'4; and 26: are. connected by a conductor 2-3.- to. a compensating winrhng ot the high voltage secondary winding 1. The systemthus far described diiiers very little from that shown and claimed inthe above mentioned patent and hence functions in the identical mannerto record the true useful current flowing through the X-ray tube.

Inaccordance with the present invention, however, a discharge devicesuch as a neon lamp 29- provided with electrodes at and c andsh-unted'by a resistance 30 for limiting the current passing through thelamp, is interposed in the conductor 28 and thus in series with therectifying bridge arrangement for the meter 22-. During each half waveof the alternating current cycle when cur-- rent fiows through thesecondary winding 1, it also flows simultaneously through the lamp 29,with its inherent A. G. sine- Wave, although flowing unidirectionallythrough the meter 22 due to the rectifying arrangement.

Accordingly, when current is flowing through the high voltage energizingcircuit for the X-ray tube and simultaneously through the neon lamp 29both electrodes at and c of the latter will glow. This will be betterappreciated if it be assumed that at a given instant the end of thesecondary winding 1 connected to the cathode of high voltage rectifyingvalve 9 is negative then such valve tube, as well as the valve tube M,will be conductive and high voltage electrical energy will flow throughthe X-ray tube and back (through rectifier M) to the other end of thesecondary winding 1. At this same instant that rectifying valves 9 and Mare conductive, current is flowing through the meter circuit in onedirection and electrode a. of the neon lamp will glow since the latteris so connected that electrode a is momentarily positive when valves 9and is are conductive.

During the next half wave of the alternating current cycle the polarityreverses so that high voltage rectifiers iii and I3 become conductivewith reversal in the direction of current flow through secondary winding3 as well as through the meter circuit so that electrode of the neonlamp 29 now glows. Consequently if one electrode of the neon lamp glowsduring one half cycle when current is flowing through high voltagerectifying Valves 9 and i i and the other electrode glows when currentis flowing through rectifying valves 10 and i3, then the visual orindicating effect of the neon lamp to the operator is that allrectifying valves are properly functioning because both electrodes ofthe neon lamp would be glowing.

If, however, in the case assumed either of valves 9 or I4 becomesdefective, then the electrode a ceases to glow indicating one or bothhave failed; and in a similar manner, should the electrode 0 of the neonlamp 29 cease to glow, this indicates that one or both of the rectifyingvalves III or l3 have become defective.

It will thus become obvious to those skilled in the art that an X-raysystem is herein provided in which an indicator in the form of a neonglow lamp is utilized to give an indication to the operator whether ornot the high voltage rectifying valves are properly functioning. Shouldone fail the apparatus is immediately de-energized b the operator thusavoiding the possibilit of making faulty radiographs with wastage offilm.

Although one embodiment of the present invention has been shown anddescribed, it is to be understood that still further modificationsthereof may be made without departing from the spirit and scope of theappended claims.

I claim:

1. An X-ray system comprising an X-ray tube, a high potential source ofalternating current electrical energy, rectifying means connected tosaid source and to said X-ray tube for converting the energy supplied tosaid X-ray tube into unidirectional current, and means connected to saidhigh potential source and in series with said X- ray tube but subject toa slightl less current flow than said X-nay tube and operable duringeach half wave of the alternating current cycle to indicate to anoperator the particular sine of the alternating current cycle normallypassed by said rectifying means and to identify the particul-arrectifying means upon failure thereof to pass current of a given sinewave.

2. An X-ray system comprising an X-ray tube,

a source of alternating current electrical energy,

including a transformer having a high potential secondary winding,rectifying valve tubes connected to the high potential secondary windingof said transformer and to said X-ray tube for converting the energysupplied by the secondary winding to said X-ray tube into unidirectionalcurrent during the entire alternating current cycle, and indicatingmeans connected to a portion of said high potential secondary windingand in series with said X-ray tube and subject to a current flow oflesser magnitude than that supplied to said X-ray tube and operableduring the entire alternating current cycle to indicate to an operatorthe particular sine of the alternating cur-rent cycle normally passed bysaid rectifying valve tubes and to identify the particular rectifyingvalve tubes upon failure thereof to pass current of a given sine wave.

3. An X-ray system comprising an X-ray tube, a source of alternatingcurrent electrical energy including a transformer having a highpotential secondary winding, rectifying valve tubes connected to thehigh potential secondary winding of said transformer and to said X-raytube for convertin the energy supplied by the secondary winding to saidX-ray tube into unidirectional current during the entire alternatingcurrent cycle, and a glow lamp having electrodes therein connected inseries with said high potential secondary winding of said transformerand said X- ray tube and operable during the entire alternating currentcycle to indicate to an operator the particular sine of the alternatingcurrent cycle normally passed by said rectifying valve tubes and toidentif the particular rectifying valve tubes upon failure thereof topass current of a given sine wave.

4. An X-ray system comprising an X-ray tube, a source of alternatingcurrent electrical energy including a transformer having a highpotential secondary winding, rectifying valve tubes connected to thehigh potential secondary winding of said transformer and to said X-naytube for converting the energy supplied by the secondary winding to saidX-ray tube into unidirectional current during the entire alternatingcurrent cycle, and a glow lamp having electrodes therein comiected inseries with said high potential secondary winding and said X-ray tubeand operable during the entire alternating current cycle to support aglow discharge at one or both of its electrodes to indicate to anoperator the particlar sine of the alernating current cycle normallypassed by said rectifying valve tubes and to identify the particularrectifying valve tubes upon failure thereof to pass current of a givensine wave.

5. An X-ray system comprising an Y-ray tube, a source of alternatingcurrent electrical energy including a transformer having a highpotential secondary Winding, rectifying means connected to saidsecondary winding and to said X-ray tube for converting the energysupplied by said secondary winding to said X-ray tube intounidirectional current, a metering circuit including said X-ray tube andsaid high potential secondary winding which carries a capacity currentdue to the capacity of the high potential circuit and including a meterfor measuring the current supplied to said X-ray tube, and meansconnected in series with said meter for indicating to an oper- .failurethereof to pass current of a given sine wave.

6. An X-ray system comprising an X-ray tube, a source of alternatingcurrent electrical energy including a transformer having a, highpotential secondary winding, rectifying means connected to saidsecondary winding and to said X-nay tube for converting the energysupplied by said secondary Winding to said X-ray tube intounidirectional current, I2, metering circuit including said X-ray tubeand said high potential secondary winding which carries a capacitycurrent due to the capacity of the high potential circuit and includinga meter for measuring the current supplied to said X-ray tube, and aglow lamp provided with electrodes connected in series with said meterand operable by the occurrence of a glow discharge at one or both of itselectrodes to indicate to an operator during the entire alternatingcurrent cycle the particular sine of the alternating current cyclenormally passed by said rectifying means and to identify the particularrectifying means upon failure thereof to pass current of a given sinewave.

7. An X-ray system comprising an X-ray tube, a source of alternatingcurrent electrical energy including a transformer having a highpotential secondary winding, rectifying means connected to saidsecondary winding and to said X-nay tube for converting the energysupplied by said se'c ondary winding to said X-ray tube intounidirectional current, 'a metering circuit including said X-ray tubeand said high potential secondary winding which carries a capacitycurrent due to the capacity of the high potential circuit and includinga series connected meter for measuring the current supplied to saidX-nay tube, a glow lamp provided with electrodes connected in serieswith said meter and operable by the occurrence of a glow discharge atone or both of its electrodes to indicate to an operator during theentire alternating current cycle the particular sine of the alternatingcurrent cycle normally passed by said rectifying means and to identifythe particular rectifyin means upon failure thereof to pass current of agiven sine wave, and an impedance connected in shunt to said glow lampfor limiting current flow in the latter.

CHARLES T. ZAVALES.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,703,147 Holden Feb. 26, 19292,128,080 Dawson Aug. 23, 1938 2,212,025 Kent Aug. 20, 1940 2,232,284TiSZa Feb. 18, 1941 2,244,137 Bischofi et a1 June 3, 1941 2,322,404Weisglass June 22, 1943 2,411,848 Camras Dec. 3, 1946

